Flying-machine supporting surface



H. JUNKERS FLYING MACHINE SUPPORTING SURFACE H9 4 Filed June 26 1920 a $hes'ts-5h0oi; 1 1

[m vewiam- July 24, 1 923. 1,462,704

H. JUNKERS "FLYING MACHINE SUPPORTING SURFACE Fi led June 26 1920 n sums-sum a liflll f-ii'l IIIIIIIHHM July 24, 1923. l E MZUWM H. JUNKIERS FLYING MACHINE SUPiORTING SURFACE filed 'Jun'. 2s 192a fi m. j

Patented July 2 4, 1923.

.NITED mar/ea mroo .nmxnns, or aaonnn-rnannamamae; enema.

FLYING-MACHINE SUPPORTING SURFACE.

Application filed June 2, 1920. Serial No. 992,141.

(GRANTED UNDER THE PROVISIONS OF i=5 1 faces (for which I have filed application in Germany, December 22, 1916; Germany,-

June 26, 1919; Austria, February 11, 1918;

Holland, July 29, 1919; Sweden, December 18, 1919; Switzerland, December; 23, 1919; Denmark, December 31, 1919; Norway, January 17, 1920; Czechoslovakia, January 17, 1920), of which the following is aspecification. A

My invention. refers to supporting surfaces for flying machines and more espe-- cially to all-metal surfaces of the self-s11 porting type, i. e'. such as are not external y stayed or stiffened.

Now the customary manner of constructing the supporting surfaces of flying machines consists in covering a frame-composed as a rule of two longitudinal beams and a plurality of cross beams (frames or ribs) with a covering of cloth, or the like.

Thecssential drawbacks appertaining to this form of construction reside in the use of elastic material for the covering, which at best is suitable for thetransmls sion of 'tensile forces. Thusthe fact of the covering bein elastic renders it necessary, forexample or the purpose of securing and maintaining the proper shape of the supporting surfaces, as also for taking up twisting strains to arrange a great number of cross .beams or transverse girders, as a consequence of which the construction of the surface is rendered more difiicult, and its weight increased. Moreover, for the pur- 'pose of transmitting the forces of air resistance acting on the surface itis as a rule necessaryto interpose a special connection resistive againstair pressure between. the

longitudinal beams and the cross "frame According to my present invention, now, the supporting surface has the form of a hollow body comprisin a number, of beams disposed in the longitu supporting surface" and preferably, constructed after the manner'of lattice girders, 'and a sheet metal covering, entirely enveloping said girdersyand provided with protruding'portions such as corrugations, or

inal direction of the ACT 01 MARCH 3, 1921, 41 STAT. I, 1319.)

the like, extending in the direction of flight,

and serving to reinforce the covering, which latter is rigidly connected with the various parts'of the frame at various points, distributed all over the wing surface.

This novel form of wing construction involves a number of highly important advantages, as will be explained in full hereinafter.

, Owingto the peculiar profile given to the sheet metal covering, the possibility is afforded of roviding a cover, even with sheet metal of slight thicknessysuchas is required to avoid too large an ,increase in weight which possesses a suficient rigidity of its own to enable it to transmit both the forces coming to act on it perpendicularly and tending to deform the cross sectional shape of the supporting surface (such as air pres sure, local loads, as when, for instance, the

wing is being trod on), as also the forces acting in the directlon of the profile given to the sheet metal, and all this without any excessive alteration of shape andfor rela-' tively big distances. The fact that the im-. proved cover constitutes in and for itself a rigid body, renders it possible to trans fer to it either partially or even entirely the functions which it was hitherto necessary to provide special members in the wing frame for.

For this reason, the transverse beams or girders (cross-frames, ribs) which were otherwise required for the purpose of securing the true cross sectional, shape of the wing, for the mutual connection of the longitudinal beams, and it)! taking up the twisting strains, may now be dispensed with either in part or entirely. 'Besides,

the covering may itself constitute the air pressure resisting connection between the singlelongitudinal beams. By these means, the construction of the wing is simplified to a very considerable extent.

In the event of a member or section of the frame being damaged, the forces which would otherwise be taken up by this particular member or section, may be transmitted through the cover across the section damaged, or else transferred to adjoining portions of the frame, so that thereby the safety of the novel supporting surface, even.

in the event of any section thereof being injured, is merges 4 The main beams disposed in the longitudinal direction of the wing, are preferably constructed after the manner of panel works composed of tubes; Now, in accordance with the factjthat the load diminishes towards the free ends of the supporting sure faces, the top ,and bottom flanges of said girders are suitably composed of members or sections of different diameter or different wall thickness. Y

It will. also be found expedient to so dispose the cover that the raised portions thereof, facing the inner side of -the wing, will come to repose directly upon the top and bottom .flanges of the main girders f the 'cover be then rigidly connected at every point of contact with the frame girders, say

In the case of supporting surfaces of the.

kind hereinbefore described, the twisting (torsional forces arising in the wing are also for t e main part transmitted by the cover, which in this. case is subjected to shearing stresses. In particular in the case of lar sized suppor-tmg surfaces, i. e. such wherein the'distance between the longitudinal beams or girders is relatively large, it has been found that the sections of the wing covering located between two such beams or ,girders on being subjected to great strains v W111 more and-more tend to lose their original shape, which will in one course lead to the, wing cover bulging out and crumpling up. This drawback may be successfully overcome by arranging between the longitudinal beams or girders on the corrugated sheet metal and firmly fasteningto this latter, special stays in such wise that the said stays will crossthe corrugations formed in the win cover either obliquely .or vertically. The action of these stays is such that both in the case of locally confined strains as also in that of more extended strains exerted on the wing cover, the normally corrugated shape, and therewith the power of resistance prema pro r to the wing cover, cannot be ture y impaired or lost.

By the provision of stays or stifiening members 0 the said kind the wing coverincreased shearmg stresses. To utilize this fact to the .utmost extentossible, and accordingly to be able to safely transmit even increased shear mg forces from the cover to the pointwhere the wlngs are secured (wing base or girder junction points), respectively, at the points of division between one wing section and another, the cover is suitably reinforced at the said points of connection or division by additional members serving for the transmission offorces, disposed. in the plane'of division, of the wings or inthe plane of the girder junction from irder to girder, that is to say, about vertica ly to the irders- The front face of the wing, t e so-called wing head is not as a rule provided with a sharp edge, but is rounded off. As this rounded off portion a rather small radius relatively to te profile formation of the remaining wingsection, it is somewhat difiicult to bend the corrugated or otherwise shaped sheet iron into this particular form. It will therefore be foundexpedient to con-. struct the wing head as a distinct part, duly connected with the upper and lower portions of the cover which are likewise constructed separately for themselves. In this connection, it is again possible to carry this out in -manifold ways. Thus, -for example, the head may be primarily constructed after the manner ofa channel or groove, the internal extremely bent portion of which is level, while the two lateral portions, which are less curved, are provided with corrugations, or the like, gradually increasing in depth toward the outside, and corresponding in ,shape to the profile formation of the wing covering. However, the head ofthe wing may also be fitted out with through going corrugations or the like, formed by means of special dies, or else by forging, or a similar operation. Finally, the rofile formation of the win cover may so be made to gradually run own to a level surface'in the direction toward the junction int for the head which, for its part, is in t e main also leve In the drawings aflixed tothis specification andv forming part thereof several modifications of the subject'matter of my invention are illustrated diagrammatically. In

the drawings-,-

Fig.1 is a cross section of a supporting surface, Fig. 2 a longitudinal section,

Fig. 3 a plan with part of the cover removed. Fig. 4 is the cross section of another modlfication.

Fig. 5. is a side elevation of a longitudinal beam or girder;

Fig. 6 is a cross section-of a particular profile formation;

Figs. 7 to 12 are details showing the manner of attaching the corrugated or otherwise shaped sheet metal to the frame girders;

Figs. 13 to 15 illustrate one modification of the terminal edge of the wing, while Figs. 16 and "17 show a formof execution of the head,

onroe Figs. 18 to 20 illustrate a supporting surtion of the supporting surface.

Referring to the drawings, the frame ar-,

ranged within the interior of the hollow supporting surface according to Figs. 1 to 3 consists of a relatively large number of longitudinal lattice girders, comprising a top flange 1, a bottom flange 2, perpendicular stays '3, and diagonal stays 4. A cover 6 consisting of corrugated sheet metal is fitted across the frame, being rigidly jointed to the flanges 1 and 2 at thesunken portions 7 of the corrugations. The said cover thus constitutes a substitute for the resisting (ionnection otherwise required to be'arranged between the single main girders of the frame for. the purpose of takingup the forces that come to act upon them porting surface in a horizontal directioniagonal rods are arranged to run from the bottom flange of the-one; longitudinal girder to the top flange of the adjacent girder, said rods, conjointly with cover 6, enabling the wing to take up torsional stresses. v I

Fig. 4 is a cross sectional view of a wing .similar to that shown in Fig. 1, the difi'er- .ence being that in this case the top and bot- ;tom' flanges of the main girders are staggered so that the frame cross'section will be composed of approximately equilateral triangles. The top and bottom flanges 1 and 2, (Fig. 5) are composed of tubular memhers, the diameter of which 'graduall lessens in the direction toward the wing en In the modification illustrated in Fig. 6, the profile formation is reinforced at certain points, distributed over the full length of the wing, for the purpose of rendering thecover still more capable of resistance against deformations, in other words to render the entire supporting surface still more rigid,

without, however, essentially increasing the weight thereof. The covert, possessmg a profile formation of any kind whatsoever, and fixed to the frame section 1, is provided .at certain interval's with projections 9, 10' either disposed along-the outside over the entire width pr the wing, or else, arranged within the wing between always two longitudinal girders; said projections, while hav ing a greater depth, preferably resembling in shape the general profile formation, an

' they may either be integral with-the sheetmetal cover (as at 9),or else they may be superposed separately, as shown at 10. ese projections may further be reinforced by providing them with corrugations in the manner shownat 11.

a Fig. 7 illustrates a simple way of attachsheet metal cover fifthis latter being also.

corrugated. In the sunken portions 7 of the corrugations, the strip 16 is ri 'dly joined to the clip 18, said clip being cfimped to the frame member 1. By these means any weakening of sections of the frame owin to the presence of rivet holesis avoide while moreover the number of fastening points between the frame section and the cover is fur-' ther increased, in consequence of which arrangement the distribution. of force over the sheet mgtal coverdis enihancedfto 3. still greater e e,'an an an r o sai cover being wre-i i l ied ofl' is obvia ttd.

A similar form of joint is shown in Figs. 10 to 12. In this case, a clip 20 serves to ,connect the sheet metal cover 6 to the frame member 1, the upwardly bent laps 21 of said clip being attached to the corrugated or otherwise sha edsheet metal in the vicinity'of its neutra layer.

Figs. 13 to 15 illustrate one form of construction of the rear edge of the supporting surface. The corrugations formed in the upper section 25 and in the lower section 26 of the wing, respectively, are staggered for the distance of half apitch relatively to each other, so that the corrugations at the rear edge of the wing will converge to a sharp edge 27 running in a line with the corrugations of the wing cover. For the purpose of connecting the upper and the lower wing sections 25, 26 at the rear edge of the wing,

both sheet metal sections are fixed to a wedge 28 of wood, or the like, in the faces of which corrugations are formed corresponding to/those of the wing cover.

Figs. 16 and 17 are, respectively, a cross per and lower wing faces'relatively to eachother in order to secure their convergingsmoothly at the rear edge of thawing.

' In the win structure shown in Figs. 18

to 20, stays are arranged along the lower wing face between. the bottom flanges for means of rivets suitably staggering-the profile formation of the up- Mid illlti section and a front view of a specially con- Flu the purpose of increasing the resisting capacity of the sheet metal cover against torsional or shearing stresses. These reinforcing sta s are disposed in a line with the longitudinal beams, and similar to these, they are ri 'dly connected to-the corrugated sheet meta say by riveting. In the example illustrated, the cross sectional shape of these stays is that of a corrugation, however, also other cross sectional forms may-be made use of. In the case of large sized supporting surfaces there may be arranged between each pair of longitudinal (girders a plurality of sta s ,of this kind, an these latter may in ad ition be provided with special props supporting them relatively to the girders. Thus, for instance, the reinforcing stay of the central. field is propped up by, means of the rods 33 relatively to the oppositely disosed top flange common to the adjoining ongitudinal girders.

' According to requirement either all, or else only some of the corrugated sheet metal sections disposed between the longitudinal girders may be provided with such reinforc-- ing stays.

The reinforcing members 31 disposed in v a line with the corrugations are connected at the junction point of the wing with the edge of the corrugated sheet metal, th ends of said members being connected to the bottom flanges 2, which thus effectively assist the wing cover in transferring the shearing forces on to the points of junction with the longitudinal beams. The aforesaid reinforcing members may, moreover, bearranged. as shown in the ,draWing either only between always two longitudinal girders within the 'fields or wing sections subjected to the, greatest amount of strain, or else around the entire cross sectional area of the wing. 1

In a like manner, other hollow bodies appertaining to air craft, and subjected to stress in the same way as the supporting surfaces, such as rigid rudder surfaces (socalled fins) and the like, may be constructed in a similar manner, in" accordance with this invention.

..Iclaim:

1. In a flying machine surface in combination, a plurality of longitudinal girders and a sheet metal covering surrounding the said girder structure and connected therewith in a plurality of places, said sheet metal coyermg being provided with narrow corrugations substantially unifonmy extending in the direction of flight over the -'entire length of said covering.

2. a flying machine surface in combinatlon, a plurality of longitudinal girders converging-towards each other and having each one flange in common with the adjacent girder and a sheet metal covering sur- 'a sheet metal covering rounding the said girder structure and con nected t erewith in a plurality of places.

3. In a flying machine surface in combination, a pluralit of longitudinal girders convergin towar s each other and having each one ange in common with the adjacent irder and a sheet metal covering surroun ing the said girder structure and connected with the top and bottom flanges respe'ctively, of said girders.

4.- In a fl ing machine surface in combination, a p urality of longitudinal girders, a corrugated sheet metal covering surrounding the said girder structure, a corrugated reinforcing member closely applied to the inner side of said covering and clamping means adapted to connect said covering wit said 'rders.

5. n a ti machine surface in combination, a.p urality of longitudinal girders and a sheet metal covering surrounding the saidgirder structure and connected therewith in a plurality of places, said sheetrection of flight, the corrugations on the.

upper and lower portions of the covering being'stagged in such a way as to form a lfreen edge at the rear end ofthe said surace.

6. In a flying machine surface in combina tion, a plurality of longitudinal girders and surrounding the said irder structure an ma plurality of places, said covering being provided with corrugations substantially.

extending in the direction of flight, the corrugatlons on the upper and lower portions of the covering being staggered in such a connected therewith way asto'form a'keen' edge at the rear end of said surface, and the rounded head portion being formed of a plain sheet metal.

7 In a H ing machine surface in combination, a p urality of longitudinal -girders and a sheet metal covering surrounding the said girder structure and connected thereseparate piece ofi with in aplurality of places, said covering being composed of aplurality of separate parts, the rounded head portion formed of plain sheet metal and the tog portions formed of corrugate said portions being fixed to each other in any suitable manner.

8. In a flyin machine surface in combination, a p ura and bottom portions fixed to each other in any suitable manner, said top and bottom portions being provided with corrugations.

and bottom 1 sheet metal,

'ty of longitudinal er'sand a sheet metal covering surroundi d the staggered in such a way as to form a keen edge at the rear end of said surface, while the said head portion has corrugations formed thereon which extend in an oblique direction so as to connect the staggered corrugations of the said top and bottom portions.

with corrugations substantially extending transversely to said girders surrounding said girder structure, and stiffening members extending substantially in parallel with and between said girders, said covering being fixed to said girders and said stiffening members.

11. In a flying machine surface in combination, a plurality of longitudinal girders, longitudinal stiffening members extending substantially in parallel with and between said girders, a sheet metal covering surrounding the said girder structure and said stifiening members and connected therewith in a plurality of places and stays between said stifi'ening members and the opposite flanges of said girders.

In testimony whereof ll aflix my signature.

nneo anmrnns. 

